FEBRUARY 2007

PRIMEFACT 525

(REPLACES AGFACT P2.4.3)

Pastures for horses
Hugh Allan Former District Agronomist Rod Hoare Former State Equine Veterinary Officer Carol Rose District Agronomist, Extensive Industries Development, Kempsey stocked with the result that the pasture is damaged and only the toughest plants or weeds survive. Supplementary feeding also guarantees feed quality and quantity and counters seasonal fluctuations in pasture supply. Species or varieties do not define a high duality pasture. They are important, but the management of the pasture is just as important. Grazing in the early vegetative stages, having a mix of legumes and grasses, applying adequate fertiliser, weed control and maintaining sufficient moisture will affect the quality and feed value of the pasture. A critical time of the year is July/August when mares heavily in foal have to eat pastures that are frost affected. Frost-affected kikuyu, paspalum and couch are adequate if clovers are in the pasture mix. High quality pasture is essential when a mare foals to ensure that the mare produces enough milk to support her rapidly growing foal. Also, it is important that the mare does not lose condition at this time because she will be mated for next year's foal. For further information on feeding requirements of horses read Primefact 425 Practical feeding of horses, Primefact 526 Feeding the brood mare, and Primefact 527 Feeding the working horse.

Introduction
A good pasture will meet the nutritional needs of most horses including brood and lactating mares and growing foals, although working horses may require some supplementation. However, the grazing habits of horses require that special consideration is given to the selection and management of the pasture. Because of New South Wales' range of soils and rainfall, no single pasture species suits all horse properties. Select pastures suited to your area and then select from these the most suitable for horses.

Why are horses and the management of their pastures special?
• Horses have a different digestive system to cows and sheep. Cows and sheep have four stomachs, horses have one stomach and a well developed large intestine. This limits the digestion of low quality feed and increases grazing time for horses. As a general rule, a 500 kg horse will eat less than a 500 kg cow but a horse wastes more pasture. The stocking rate for horses is similar to that of cattle. • Horses are very selective in their grazing habits. They prefer certain pastures and crops and leave species that are unpalatable. These `weeds' can soon dominate more desirable species.

Well managed high quality pastures can meet the nutritional needs of most horses including brood and lactating mares and growing foals.

Feed requirements of horses
Recent research has shown that high quality pastures can meet the feed requirements of horses. However, most horse establishments supplementary feed their horses because they are held in confined areas where they can be checked on a regular basis. These areas are usually set

and white clover. and a spring pasture. It will not persist under dry conditions. Endophytes can affect the acceptability of the pasture. When selecting ryegrasses and fescues check the endophyte status. fescue. Stud breeding farm A stud-breeding farm standing a stallion has a great demand on its pastures in spring and summer. • Select pastures and crops suited to the area. because winter is the period of poorest pasture growth it may be necessary for some form of winter pasture or winter crop to be grown or a supplementary feed provided. cocksfoot. It requires high rainfall or irrigation. red and sub clover and/or lucerne is quite acceptable for horses. Visiting mares arrive as early as August and leave in January A suitable pasture for a stud-breeding farm would be a summer growing pasture that is well adapted to that area. phalaris. Some varieties have a longer growing season and are not as prone to go to seed as early as the naturalised strain of prairie grass which starts seeding in August/September. cocksfoot.
PRIMEFACT 525. The previous year's yearling foals will require pasture during the summer period. The plants tend to become tussocky and coarse and less acceptable to horses in later years. assuming these species are well adapted to the area. fescue. Thus. the `lawn area' becomes depleted of nutrients that are moved to areas where the horses prefer not to graze. Fescues and ryegrasses can contain endophytes. Phalaris Phalaris sown with white. Horses do not like to graze where there is horse manure. ryegrass (all or one of the preceding) and sub clover and white clover. pleasure horses These horses need a continuity of feed throughout the year. Fescue
What type of pastures do your horses need?
The horse industry comprises many types of horse enterprises.
Fescue pastures are very acceptable to horses in the first year of growth. A paddock stocked with horses will have a short cropped `lawn area' where the horses graze and long rank areas where they defecate. lucerne. During periods of feed shortage or without rotational grazing. and good grazing management to persist. At these times horses may be better managed by keeping them in a stable and/or yard with supplementary feed and letting them out to graze for limited periods.
Suitable species
Grasses Prairie grass Prairie grass is very acceptable to horses. Because stocking rates are low in autumn and winter. The mares are at the farm from February to July/August. Rotation of paddocks is critical with horses. ryegrass. Fescues prefer moist areas. e. PASTURES FOR HORSES
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. requires special consideration. especially the management of manure and application of fertiliser.g. However. A suitable pasture in this situation is a winter growing pasture comprising phalaris. Most enterprises can be divided into one or more of the following. They are bred into ryegrass and fescue to improve the plants' tolerance to insects and to improve productivity. kikuyu or lucerne. It must be rotationally grazed to allow seedhead development in spring and good growth after autumn breaking rains. sub clover. the desirable pasture species are eaten out and the pasture deteriorates rapidly. good soil fertility. desirable. e. Prairie grass performs well on very fertile soils under favourable growing conditions. Broodmare farm A stud farm not standing a stallion has feed requirements opposite to that of a stud-breeding complex. Ryegrass Ryegrass is a lush. Always have spare paddocks to allow rotation.• Horses prefer short pastures to tall pastures. making management difficult.
Riding hacks. this is an ideal time to get pastures and crops established for spring and summer. Only in drought conditions or in overstocked paddocks will horses graze up to manure pats. ultimately affecting livestock performance. • Management of pastures. cool season pasture for horses. These areas are prone to damage by horses. then select from that list the pastures and crops that horses prefer.g.

See Table 1. Most clovers and medics (including lucerne) have ratios in excess of 2:1. Ryegrass late veg.3 10.
Metabolisable Energy 10 9 8. Couch grass Couch grass has often been regarded as a weed. Mares grazing lucerne or eating lucerne hay with excessive leaf spot may have fertility problems. Lucerne Lucerne is another popular legume for horses. Horses readily accept subterranean clover. Calcium problems associated with pasture species The ideal calcium to phosphorus ratio for horses is 2:1.48 : 1 4. PASTURES FOR HORSES
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. In some cases the ratio may be 0. White clover late veg. more suited to non-coastal situations. This deficiency can be overcome by supplementary feeding a calcium supplement (see below) or by overseeding ryegrass and clover into the kikuyu in autumn.5 : 1 1.4 : 1 1. White clover White clovers are not readily accepted. Rotational grazing is especially important when managing lucerne as it allows the plant to build up energy reserves and to persist. It thrives in the tableland areas of New South Wales.0 8. Oats early veg. Red clover Red clover has always been regarded as a most acceptable clover for horses because of its summer growth habit. Kikuyu early veg. Cocksfoot dominant pastures in South Africa have caused calcium deficiency in horses.5:1 4. However. clovers and medics in the pasture mix will overcome this problem. Some older varieties contain high
oestrogen levels. very hardy and capable of tolerating high stocking rates on poorer sandy soils.5 11.0
Crude Protein %) 22 18 16 22 18 20 17 23 18 16 13
Ca : P (g/kg) 4.48 : 1 1. Always select a low oestrogen variety as infertility has been reported in broodmares grazing high oestrogen varieties. White clover early veg.1 : 1 1. Kikuyu Kikuyu is the most common coastal NSW horse pasture because of its ability to persist. Pastures that are over-fertilised with effluent run-off and are very lush can be a problem. However.3 : 1 5. It contains an oxalate that inhibits the uptake of calcium.5 12.5 12 11. It is adapted to many horse areas. the lusher a grass is the lower the calcium to phosphorus ratio.57 : 1 4.3: 1 1.Cocksfoot Cocksfoot is more suited to high altitudes. Including grasses.3 : 1 1. Oats late veg. In most cases horses prefer to graze other pasture species and weeds in the paddock. Lucerne late veg. white clovers should be included in pasture mixes because they are widely adapted to coastal and milder inland areas. It is very acceptable to horses. To increase persistence and yield it is important that the plants are not overgrazed.5 8. Lucerne is susceptible to leaf spot diseases. Kikuyu late veg. Lucerne flowering Ryegrass early veg.8:1.2 11. Most grasses have calcium to phosphorus ratios of 1:1. Subterranean clover Sub clover is a self-regenerating annual with winter spring growth habit.1:1
PRIMEFACT 525. Camdairy)
Pasture/crop Lucerne early veg. Feed value of common horse pastures and forage crops on a dry matter basis (Ref.
Table 1.

and of the urethra in the stallion and gelding. Effect of calcium:oxalate ratio on availability of calcium (adapted from Hinz. Always check with the seed company for recommended grazing and cutting heights.6 percent oxalate. There needs to be more calcium than oxalate in the pasture for the calcium to be available. forage sorghums are reported to cause an increasing number of cases of `Cystitis syndrome' in horses. Berseem clover.
PRIMEFACT 525.36 0.11 0. Winter For winter feed the most acceptable or preferred crops in order are triticale. hybrid forage sorghums and sudan grass. The condition causes irritation of the urethra and vagina in the mare. supplement with a feed that is a good source of calcium such as lucerne hay. Alternatively.66 kilograms of dicalcium phosphate mixed with 1. it means none of the calcium is available to the horse. sudan grass hay.08 1. PASTURES FOR HORSES
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. They grow actively from November to March. Horses do not like grazing the millets. has been sown with ryegrass as a pasture.27
Oxalate % 0. So far as is known.13
Ca availability 99% 76% 100% 17% 42% 20% 0%
Horses grazing some tropical grasses for extended periods can suffer `Big Head' disease or Osteodystrophia fibrosa.26 0. barley. The millets have an advantage over the hybrid sorghums and sudan grasses in that they do not cause prussic acid poisoning. Good mixtures are 1 kilogram of rock phosphate mixed with 1.1:3. Horse breeders have accepted for many years that barley was the most acceptable but recent observations at Hawkesbury Agricultural College indicate that triticale is the most acceptable. pearl millets. setaria. Another symptom is muscular incoordination in the rear quarters.40 0. baled wet it is fed to thoroughbred racehorses in work at the major racetracks in Sydney.25 0. In areas of south-western United States. These grasses are buffel grass. para grass.
Saia oats. Farmers have experimented with various crops with little success. Calcium oxalate is insoluble and unavailable to the horse. They prefer to graze summer grasses that might be growing in the paddock. The horses will then selectively eat the seedheads.80 0.06 0. hybrid millets. It has a calcium to oxalate ratio of 0. pangola grass and signal grass.30 1. hybrid sorghums and sudan grass.79 1. buffel and kikuyu pastures.38 0.45 0. 1990)
Names Flinders grass Rhodes Oaten chaff Buffel Green panic Kikuyu Narok setaria
Calcium % 0. The hybrid Sudan grasses are the best sorghum.28 0. Narok setaria has 0.33 kilograms of ground limestone and 0.23 0.32 0.Table 2. a winter/spring growing legume. may be used without danger. Summer Summer feed has often been a problem on breeding stud farms. The cause of the problem is a high level of oxalates. Mineral supplement mixtures that provide the required amount of calcium to phosphorus should be made available to horses grazing setaria. ryegrass and oats.5 kilograms of molasses or 1 kilogram of a mixture of 1.27 percent calcium and 1.5 kilograms of molasses. guinea grass.08 percent oxalate and 100 percent of the oaten chaff calcium is available. is totally unacceptable to horses until it goes to seed.60
Ca oxalate 1. However. See Table 2.11 percent calcium with 0.49 0. green panic. The most common summer forage crops are shirohie and japanese millet. one of the most productive oats. In the County of Cumberland it is gown as a winter forage crop for horses.92 1.
Fodder crops
Fodder crops are usually grown in rotation with pastures providing feed when pastures are not actively growing. kikuyu. Oaten chaff has 0.81 1. sudan grass options because they have lower prussic acid and thinner stems with more leaf. if properly cured. Because oxalate dominates.

sulphur. The most common nutrient deficiencies in New South Wales soils are phosphorus. sowing in August is an option. 10 t/ha) to get the best results. Excess molybdenum can tie up copper. spring annuals and summer annuals. potassium.Establishing pastures for horses
Soil fertility A property can have many different soil types. A Guide to Stocking Rates on small holdings
Pasture Highly pasture improved with summer and winter pasture species. Remember that each property.
Horses per 2 hectares 4
2
1
Note: the above is only a guide to assist new horse owners. A soil test will provide the level of available soil nutrient. phosphorus. Then a fertiliser program needs to be developed for the property. The subtropical grasses like kikuyu must be sown from October to March when soil temperatures are high. sowing into a prepared seedbed may be the best option. particularly phosphorus. It is a low analysis (approximately 3:2:1 N:P:K) organic fertiliser that must be applied at heavy rates (e. High rates of fertiliser and irrigation. It is important to know what weeds you have before sowing a pasture. and paddocks on that property. when compared to the alternative of applying large quantities of only one nutrient. low rate of fertiliser mainly summer dominant pasture. are unique and must be treated as such. As long as a soil has adequate calcium levels and a desirable pH the addition of extra lime can be wasteful and in some cases dangerous. which ultimately means livestock performance and profitability are increased. some farmers have applied Mo single superphosphate annually over many years to find their livestock are copper deficient. To determine nutrient deficiencies and the level of nutrient deficiency. Where summer grass weeds are a problem sow in February/early March.
PRIMEFACT 525. The Sydney and Central Coast area is dominated by poor sandstone soils which have a high prevalence of kikuyu and responds well to poultry manure. In cool climates. is more critical. This is incorrect. More feed is produced and the quality of feed is better. Central Coast and Tamworth areas. It is important that all deficiencies be met because one deficiency may limit the response to the other nutrients. or by sowing into a prepared seedbed or a combination of both. Reasonable summer dominant pasture with some winter pasture species and moderate rate of fertiliser. Also horses dominate small holdings. fertiliser on a regular basis is sensible where they are all deficient. On heavily compacted soils. When applying high rates of any fertiliser it is important to understand the effect of the program on other soil nutrients. May is the preferred time for most pasture species.g. Table 3 provides a guide to desirable stocking rates. A well-planned fertiliser program can be one of the best investments on a property. molybdenum and nitrogen. Poultry manure is readily available in the Sydney. Pastures can be established by direct drill techniques (herbicides and no-till seeders). Poor pasture. therefore do not treat the whole property as if it were one paddock. Calcium. Many horse owners believe horses do better on soils that are regularly limed regardless of the soil pH. potassium. It is best applied in early spring.
Pasture management
Stocking rates The biggest problem on most horse properties is overstocking. winter. do a soil test. and sulphur. Lime is often used on acid soils to increase soil pH and calcium levels. In the past. Time of sowing March. Applying small balanced rates of nitrogen. magnesium. PASTURES FOR HORSES
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Ground preparation The most important issue in preparing a paddock for a pasture is weeds. Table 3. Therefore a relatively quick ground preparation in autumn may not control the hard to kill perennials and summer annuals. Weeds can be classified into perennial. Also the selective grazing of pastures by horses encourages weeds. Most horse paddocks have high populations of weeds because horses are supplementary fed grain that contains weed seeds. or where kikuyu is to be sown. inducing copper deficiency in livestock. copper and zinc may also be deficient in some soils. April. Cartage and spreading are difficult and costly. The amount of calcium relative to other minerals.

0 5. Although blood test is the most accurate method of determining deficiencies. low fertility or country dominated by Poa Tussock Cleared. PASTURES FOR HORSES
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. Allow horses to graze the pasture.25 2.
PRIMEFACT 525. The appropriate level will vary with the situation (soil type.0 7. mineral imbalances are hard to diagnose. with no seed or fertiliser then the horse will need 5 hectares of pasture to survive. Table 4.0 13. Care needs to be taken with lush pastures because some horses. It should be remembered that DSE ratings are a very approximate guide to carrying capacity and that monitoring and adjustments are continually needed to match the area to livestock requirements. Spreading manure droppings evenly by running a chain harrow will add fertility to the soil and spread any parasite eggs in the droppings where they can be killed more easily by sunlight. Example: A light horse has a DSE rating of 10. Livestock DSE Ratings
blood level of minerals at normal levels even when there is insufficient for normal bone growth. Urgent veterinary attention must be sought for any horse that shows a reluctance to move which might be the first stages of founder.heavy work
DSE 1. etc. At all times maintain a high level of ground cover to prevent erosion.5 18.0 14. If the horse is grazing cleared. particularly ponies.5 12. Management practices should reduce wastage of feed. Opinions differ on the management of manure droppings in horse pastures. Wait until the pasture is 10 cm in height before regrazing. They selectively graze pastures. Estimated dryland carrying capacity in DSE ratings for the Northern Slopes of New South Wales
Class of Pasture Native. no seed or fertiliser Moderate fertility. The other alternative of leaving the manure in the paddock encourages
Class of Livestock Merino wether Merino ewe Steer Cow Light horse Draught horse Pony Horse .
Grazing management
Horses are wasteful grazers.7
Determining trace element deficiencies Consult your veterinarian for advice on trace elements. moderate fertility. Collecting and removing manure will help grazing management but could lead to major nutrient deficiencies. native grasses.0 10.75–6.) For most high rainfall areas of New South Wales 90% ground cover is acceptable. The horse's metabolism will try to keep the
Table 5. native grasses plus sub-clover and fertiliser Moderate fertility sown with phalaris sub-clover and fertiliser Rotational grazed lucerne Extensively grazed lucerne Kikuyu + clover + oversown ryegrass and fertiliser (intensive)
Average DSE/ha* 1.5 8.0 1. remove the horses. slope. damaging parts of the pasture by overgrazing and leaving other parts of the pasture tall and rank and relatively unacceptable.5 cm in height over 20 percent of the paddock.75 25–30
* A ‘DSE’ is the dry sheep equivalent and is equal to the amount of feed needed to sustain a 50 kg Merino wether over a 12 month period. unimproved. native grasses. Slash or mulch the paddock and harrow the manure. moderate fertility. rainfall.5 10. even with blood tests.0 13. It is best to prevent problems by providing a good balance in the pasture. After they have grazed the paddock to 2.5–10.0 6. It is critical to apply a balanced fertiliser program with potassium if all the manure is removed. are prone to founder (laminitis) when the feed is lush.Relating the feed required by a dry sheep (wether) to the carrying capacity of land is another way of determining suitable stocking rates (see tables 4 & 5).light work Horse .

It is often confused with annual smooth catsear (Hypochoeris glabra) and dandelion (Taraxacum officinale). It is desirable to have at least 3 paddocks for a group of horses. • Horses have the ability to spread weed seeds. This allowed many of the recommendations in this Primefact to be made. better pasture utilisation. • Ross Cribb. Robrick Lodge.a versatile pasture grass • Pastures for Horses – A Winning Resource by Angela Avery.
Adequate subdivision enables rotational grazing. Ebenezer
Weed management
Weeds are a problem in horse pastures because of selective grazing by horses and also because horses are usually supplementary fed. Grose Vale • Ron & Val Males. less weeds and adequate ground cover.1 Phalaris pastures • P2. • Catsear or flatweed (Hypocboeris radicata) causes stringhalt in horses. Do not graze horses in heavily infested fields during the summer–autumn growth period. PASTURES FOR HORSES 7
. Inspect all horse pastures for this weed. Spraying with a registered herbicide or removing by hand is necessary.5 Lucerne for pasture and fodder • P2.2. Most pasture species will benefit from spelling – some to set seed and others to replenish energy reserves. will help to discourage parasites and diseases.) has improved seed germination after passing through the digestive tract of a horse. because horses have a pecking order that includes biting and kicking. The rotation of clean pastures. Colo • The White family.gov. The optimum time to graze ryegrass is at the threeleaf stage.5.au/aboutus/resources/factsheets • P2. Paddy's lucerne (Sida sp. published by RIRDC
Acknowledgements
Hugh Allan would like to thank the following prominent horse breeders of the Sydney basin who worked with him in establishing and managing high duality pastures on their properties.2.nsw. Keep horses out of the pasture during extreme wet weather to prevent 'pugging' of the soil with hooves. Castlereagh • Neil & Darcy Shedden. • Crofton weed is very poisonous to horses. They grow in the overgrazed areas of the paddock. JayR Stud. Gunderman • Fred Persiah. Nepean Stud Farm.5 Cocksfoot .dpi. Tahmoor • Bruce McHugh. Paddy's lucerne. However. The bought feed can contain weed seeds. Werombi • John Muir. many horse managers prefer to set stock paddocks with smaller numbers of horses which means that paddocks do not get a rest to recuperate. John-Sweeting and Morris (1990) suggested horses that have previously grazed weeds should be held and fed in yards or stables for 10 days before being introduced to weed-free pastures. Shipton Lodge. • Annual and perennial broadleaf weeds like Paterson's curse.4 Pasture establishment on native country: central and southern tablelands • P2. in conjunction with a good parasite control program. These weeds usually grow near fence lines and under trees. prairie grass at the five-leaf stage and kikuyu at the four and a half leaf stage. St. Cobbitty • Bob & Wendy Lapointe. Rotational grazing is a must for horses. • Advanced hepatic disease has been noted in horses grazing Paterson's curse (Echium plantagineurn) and Fireweed (Senecio madagascariensis) in New South Wales. Correct grazing management is critical in controlling weeds but particular weeds can cause problems. a practice which ensures horses are continually presented with clean pastures.
preferring sandstone and rocky escarpments. To encourage vigorous growth of pastures it may be necessary to topdress with nitrogen fertilisers such as urea and nitram. Muskoka.5. wild radish and nettles thrive in horse paddocks. Ralvon. Apply these fertilisers straight after mulching or slashing and give the paddock at least 4 weeks to regrow before grazing. It thrives on coastal hill country with high rainfall. The factsheets are available from www.
Further reading
The following factsheets contain information on pastures. Hadden Farm.
PRIMEFACT 525.selective grazing.